Extraction of methylmercury and ethylmercury from aqueous solution using surface sulfhydryl-functionalized magnetic...

Surface sulfhydryl-functionalized magnetic mesoporous silica nanoparticles were prepared, aiming to extract trace alkylmercury from aqueous solution. The prepared nanoparticles were characterized by TEM, ED, EDX, DLS, FTIR, and SERS. Compare with that the non-sulfhydryl-functionalized Fe3O4@SiO2 exhibited almost no affinity for CH3Hg(+) and CH3CH2Hg(+); the sulfhydryl-functionalized Fe3O4@SiO2 exhibited high adsorption affinity for them, resulting from chelating interaction by surface sulfhydryl group, and the adsorption was not significantly impacted by pH within the range of 3.5-9.0 or coexisting metal ions. The monolayer adsorption on surface of Fe3O4@SiO2-RSH could reach equilibrium in 2 min. Moreover, the CH3Hg(+) and CH3CH2Hg(+) adsorbed on Fe3O4@SiO2-RSH could be quickly separated from the matrix in a magnetic field and desorbed easily by acetonitrile and l-cysteine aqueous solution or HCl solution, and the recoveries were more than 80%. Findings of the present work highlight the potential for using Fe3O4@SiO2-RSH magnetic nanoparticles as effective and reusable adsorbents for extraction of ultra trace alkylmercury from environmental water samples.